Harden Maven downloads in Docker build

Dockerfile

@@ -1,7 +1,12 @@
+# syntax=docker/dockerfile:1.7
 FROM maven:3.9-eclipse-temurin-25 AS build
 WORKDIR /app
 COPY . .
-RUN ./mvnw clean package -DskipTests
+RUN --mount=type=cache,target=/root/.m2 \
+    ./mvnw -B clean package -DskipTests \
+      -Dmaven.wagon.http.retryHandler.count=5 \
+      -Dmaven.wagon.http.connectionTimeout=60000 \
+      -Dmaven.wagon.http.readTimeout=180000
 
 FROM eclipse-temurin:25-jre
 COPY --from=build /app/target/humainflow.jar /app.jar